There are a few advanced features that Kik is still missing (voice/video messages, wallpapers), but I’m perfectly happy without them. All I really wanted from Kik was an app to help me chat with my other smartphone-wielding friends in a manner that is more reliable than text messaging, and it has performed beautifully in that regard.
The only difficult thing about using Kik has been re-establishing my old contacts list, as I now have to persuade my group of friends to “leave WhatsApp, it’s better here!”.

However, this messenger app has convinced me to kick WhatsApp, Beluga, LiveProfile, and PingChat! off of my iPhone and simply stick to Kik.